Neotheropoda represents the main evolutionary radiation of predatory dinosaurs and its oldest records come from Upper Triassic rocks (ca. 219 Mya). The Early Jurassic record of Neotheropoda is taxonomically richer and geographically more widespread than that of the Late Triassic. The Lower Jurassic (upper Hettangian–lower Sinemurian) rocks of central England have yielded three neotheropod specimens that have been assigned to two species within the genus Sarcosaurus, S. woodi (type species) and S. andrewsi. These species have received little attention in discussions of the early evolution of Neotheropoda, and recently have been considered as nomina dubia. Here, we provide a detailed redescription of one of these specimens (WARMS G667–690) and reassess the taxonomy and phylogenetic relationships of the genus Sarcosaurus. We propose that the three neotheropod specimens from the Early Jurassic of central England represent a single valid species, S. woodi., and the second species of the genus, ‘S. andrewsi’, is a subjective junior synonym of the former. A quantitative phylogenetic analysis of early theropods recovered S. woodi as one of the closest sister taxa to Averostra and provides new information on the sequence of character state transformations in the lead up to the phylogenetic split between Ceratosauria and Tetanurae.
Bibliographical noteFunding Information:
We thank the following curators, researchers and collection managers that provided access to specimens under their care for the purpose of this research: Carl Mehling (AMNH), Max Langer (LPRP/USP), Daniela Schwarz (HMN), Jessica Cundiff (MCZ), Eduardo Ruigomez and Diego Pol (MPEF), Sandra Chapman and Lorna Steel (NHMUK), Erich Fitzgerald (NMV), Caroline Buttler (NMW), Sergio Martin, Emilio Vaccari and Gabriela Cisterna (PULR), Jaime Powell, Pablo Ort?z and Rodrigo Gonzalez (PVL), Ricardo Mart?nez and Diego Abel?n (PVSJ), Rainer Schoch (SMNS), Kevin Padian and Pat Holroyd (UCMP) and Michael Brett-Surman and Hans-Dieter Sues (USNM). Access to the free version of TNT 1.1 was possible due to the Willi Henning Society. Mark Witton is thanked for creating Figures 2 and 21. This project was partially funded by a Sepkoski Grant 2019 of the Paleontological Society International Research Program (to MDE). Amy Scott-Murray (Imaging and Analysis Centre, NHMUK) carried out the scanning and produced the 3D models of NHMUK PV R4840 and R3542.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology